枯草芽孢杆菌和黑曲霉固态发酵制备核桃多肽的工艺条件优化

Optimization of the Process Conditions of Walnut Meal Peptides by Solid State Fermentation-Bacillus subtilis and Aspergillus niger

本研究以核桃粕为原料,对比探究了枯草芽孢杆菌(Bacillus subtilis 10160)、黑曲霉(GIM3.452)两株菌固态发酵制备核桃粕多肽的发酵生产性能,优化了两株菌发酵条件,筛选得到了最优的发酵条件参数。首先对影响固态发酵过程中多肽产量的主要因素(发酵时间、原料粒径、发酵温度、接种量和料液比)进行了研究,并以多肽产量为评价指标进行单因素逐步优化,研究结果表明,枯草芽孢杆菌(Bacillus subtilis 10160)固态发酵条件为:发酵时间3 d,原料粒径40目,料液比1:1.25,接种量5%,发酵温度28℃,此条件发酵后核桃粕多肽含量可达243.97 mg/g;黑曲霉固态发酵条件为:发酵时间4 d,原料粒径40目,发酵温度28℃,接种量15%,料液比1:1.25,此条件发酵后核桃粕多肽含量可达158.61 mg/g。通过分子量分布测定,进一步验证了枯草芽孢杆菌固态发酵制备核桃粕多肽产量高于黑曲霉。

The fermentation performance of Bacillus subtilis（10160） and Aspergillus niger（GIM3.452） using walnut meal as raw materials was investigated. The fermentation conditions of the two strains were optimized to achieve theoptimum fermentation parameters. Firstly, the main factors affecting the yield of peptideswere determined during the solid state fermentation（SSF）. The yield of the peptides was applied as an indicator to optimize the SSF conditions for fermentation of Bacillus subtilis and Aspergillus niger, respectively. For Bacillus subtilis,the optimum fermentation time, particle size, ratio of material-to-water, inoculum quantity and fermentation temperature were 3 d, 40 mesh, 1：1.25, 5% and 28 ℃, respectively. The peptide content in the resultant fermented products reached 243.97 mg/g（relative to 50.52 mg/g in raw material）. For Aspergillus niger fermentation, the optimum fermentation time, particle size, ratio of material-to-water, inoculum quantity and fermentation temperature were 4 d, 40 mesh, 1：1.25, 15% and 28 ℃, respectively. The peptide content in the last products was 158.61 mg/g. Finally, the higher yield of peptides by Bacillus subtilis fermentation relative to that by Aspergillus niger was verified based on the molecular weight distribution analyses.